1 files changed, 103 insertions, 0 deletions
diff --git a/silx/gui/utils/concurrent.py b/silx/gui/utils/concurrent.py
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+++ b/silx/gui/utils/concurrent.py
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+# coding: utf-8
+# /*##########################################################################
+#
+# Copyright (c) 2018 European Synchrotron Radiation Facility
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+# ###########################################################################*/
+"""This module allows to run a function in Qt main thread from another thread
+"""
+
+__authors__ = ["T. Vincent"]
+__license__ = "MIT"
+__date__ = "09/03/2018"
+
+
+from silx.third_party.concurrent_futures import Future
+
+from .. import qt
+
+
+class _QtExecutor(qt.QObject):
+    """Executor of tasks in Qt main thread"""
+
+    __sigSubmit = qt.Signal(Future, object, tuple, dict)
+    """Signal used to run tasks."""
+
+    def __init__(self):
+        super(_QtExecutor, self).__init__(parent=None)
+
+        # Makes sure the executor lives in the main thread
+        app = qt.QApplication.instance()
+        assert app is not None
+        mainThread = app.thread()
+        if self.thread() != mainThread:
+            self.moveToThread(mainThread)
+
+        self.__sigSubmit.connect(self.__run)
+
+    def submit(self, fn, *args, **kwargs):
+        """Submit fn(*args, **kwargs) to Qt main thread
+
+        :param callable fn: Function to call in main thread
+        :return: Future object to retrieve result
+        :rtype: concurrent.future.Future
+        """
+        future = Future()
+        self.__sigSubmit.emit(future, fn, args, kwargs)
+        return future
+
+    def __run(self, future, fn, args, kwargs):
+        """Run task in Qt main thread
+
+        :param concurrent.future.Future future:
+        :param callable fn: Function to run
+        :param tuple args: Arguments
+        :param dict kwargs: Keyword arguments
+        """
+        if not future.set_running_or_notify_cancel():
+            return
+
+        try:
+            result = fn(*args, **kwargs)
+        except BaseException as e:
+            future.set_exception(e)
+        else:
+            future.set_result(result)
+
+
+_executor = None
+"""QObject running the tasks in main thread"""
+
+
+def submitToQtMainThread(fn, *args, **kwargs):
+    """Run fn(args, kwargs) in Qt's main thread.
+
+    If not called from the main thread, this is run asynchronously.
+
+    :param callable fn: Function to call in main thread.
+    :return: A future object to retrieve the result
+    :rtype: concurrent.future.Future
+    """
+    global _executor
+    if _executor is None:  # Lazy-loading
+        _executor = _QtExecutor()
+
+    return _executor.submit(fn, *args, **kwargs)